September 20, 2022 |

The Wyoming Game and Fish Department’s planned kill-off of fish in Saratoga Lake started on Monday. The work began with blocking access to the lake. Crews will start pumping rotenone into the water on Tuesday.

How the invasive yellow perch got into the lake remains under investigation.

Steve Gale, a fisheries biologist said that the wildlife officials believe someone illegally put the fish into the lake. Gale said all the fish in the lake must be sacrificed to stop the yellow perch from harming the native fish species downstream in the prized North Platte River system.

A team of 20 to 25 WGFD employees will use four boats to spread the rotenone. Rotenone is a natural product derived from a South American bean. It works by disabling the oxygen-uptake of gill-breathing organisms. It is not toxic to other species. The rotenone comes as a powder and will be mixed with lake water using a venturi pump. This mixture will be applied to the lake to initiate the kill-off. Gale said that WGFD will remove the dead fish.

The dead fish will be buried in pits.

The rotenone will remain active for several weeks. State biologists will monitor the amount of rotenone in the lake using rainbow trout from the Saratoga Fish Hatchery. They call these “canary fish.” Rotenone only effects fish, but people and animals should stay out of the water. Gale said the lake will remain closed until the rotenone has fully degraded. They’ll know when the canary fish don’t succumb to the chemical treatment.

Biologists want to be 100 percent certain that all the yellow perch are gone before they reconnect the lake to the water supply. The lake has been completely cut off since April. Gale said that WGFD will use gill nets and other methods to make sure that all the fish are dead.

WGFD will restock the lake with fish once they’ve completed the kill-off. It won’t happen in time to save this winter’s ice fishing derby, however.

The camp sites closest to the water at Saratoga Lake Campground have been closed during the fish kill-off. Lee Johnson, from central Missouri, was staying at the campground. She said she was saddened by how much damage and expense the illegal fish have caused.

Marty Bartow, from Georgia, has been staying at the Saratoga Lake Campground since July. He said that he was disappointed by the effect the lake closure will have on Saratoga.

The lake will remain closed until biologists are satisfied that all the rotenone has degraded. Only then can they begin to restock the lake with fish. The town of Saratoga has canceled the 2023 Ice Fishing Derby. WGFD officials have said they hopeful that the lake will return to normal by next summer.

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